After the U.S. Civil Rights Movement of the 1960s and the desegregation of public transportation and facilities and with the advancements that African Americans have gained in education, income, and employment, African Americans have greater access to travel opportunities. Today's African Americans travel in greater numbers than ever before and represent a dynamic and growing travel market segment that according to the Travel Industry Association of America (TIA) (2003) generated 75 million person trips in 2002. Although there have been several studies conducted on the differences between ethnic or racial groups with regard to their participation in outdoor recreation, research on differences between African American and White traveler behaviors in the urban tourism context is sparse. This study examined the differences between African American and White travelers who visited the city of New Orleans. Specifically, the study investigated demographic variables (income and gender) for their contribution to the differences between African American and White travelers in the modes of travel, activities participated in, sources of travel information, importance of destination activities, satisfaction with destination attributes, and spending patterns. Significant differences were found in modes of travel, activities participated in, sources of information, information of destination attributes findings (popular, African American Values, and sport and recreation), satisfaction with New Orleans on the destination attributes entertainment, African American Values, and spending. Although the findings of this study reflect the trip characteristics of travelers to New Orleans, future research should examine the applicability to other urban tourism destinations.

The Ethiopian Plateau is one of the few tectonically-active regions on Earth that is situated in continental rift zones. About 1.6 km deep gorge of the Nile was carved by the Blue Nile River on the Ethiopian Plateau, as the plateau has been experiencing continuous uplift and exhumation in the Cenozoic. Here, we used quantitative analysis of longitudinal rive-profile forms and parameters (knickpoint and normalized steepness-index ksn) of the Blue Nile tributaries to tease out regional tectonic signals. 244 knickpoints were examined in the tributaries, majority (>80%) of which are unassociated with lithology or geological structures. Knickpoint distribution throughout the plateau reveals three incision phases. The novel approach of correlation of ksn with mantle tomography suggests that higher and lower ksn values occur above low-velocity and high-velocity zones, respectively, indicating that thermal upwelling beneath the plateau linked to Afar mantle plume largely controls the uplift thus incision of the plateau.

No description available.

District heating (DH) is considered to be an efficient, environmentally friendly and cost-effective method for providing heat to buildings, since electricity is usually co-generated in biomass fuelled combined heat and power (CHP) plants. This gives it an important role in the mitigation of climate change. Swedish district heating companies are currently facing multiple challenges, and are in urgent need of new price models to increase transparency and maintain their competitiveness. This thesis describes a survey carried out to understand the structure of the present price models and subsequently proposes and compares two restructured price models with the most commonly used price model. This work also investigates the impact of restructured price models on users who would encounter a significant cost increase if the restructured price models were to be introduced. The district heating costs of different price models are compared with three alternative technical solutions. The results show that price models based on the consumption pattern of users can reflect district heating companies’ cost structure. Meanwhile, adopting a pricing strategy based on users’ consumption patterns increased the incentives to reduce the peak load. Consequently, users with high load factor (flat consecutive load curve) were able to reduce costs whereas users with low load factor (steep consecutive load curve) faced possible cost increases, when the load demand cost was changed to daily or hourly peak demand based methods. Further, the most economically preferable option for the invested district heating user was to combine district heating with direct electrical heating or with a ground source heat pump. / Fjärrvärme anses som ett effektivt, miljövänligt och kostnadseffektivt sätt för att leverera värme eftersom kraftvärme blir vanligare i fjärrvärmesystem, där elektricitet produceras tillsammans med värme. Den spelar en viktig roll i att begränsa klimatförändringen. Svenska fjärrvärme företag står inför flera utmaningar nu för tiden, och är i akut behov av nya prismodeller för att öka öppenheten och behålla konkurrenskraften. I denna avhandling, genomfördes en undersökning för att ta reda på strukturen av de nuvarande prismodellerna. Därefter föreslogs två omstrukturerade prismodeller, vars påverkan på kostnaden av fjärrvärme konsument analyserades jämför med den nuvarande modellen. Detta arbete undersökte också effekten av omstrukturerade prismodeller på konsument som skulle drabbas på signifikant kostnadsökning i samband med införande prismodeller. Kostnaden av fjärrvärme under olika prismodeller har också jämförts med tre olika tekniska lösningar. Resultatet visade att prismodeller som baserar sig på konsuments förbrukningsprofil kunde återspegla fjärrvärme företagens kostnadsstruktur; Samtidigt medförde prissättningsstrategi baserad på användarens förbrukningsprofil högre incitament för att minska spetseffekt. Följaktligen kommer att konsumenter med stabila konsumtionsprofiler att spara kostnader, medan konsumenter med spetsiga konsumtionsprofiler kommer att drabbas av kostnadsökning. Och för den investerade fjärrvärme konsument, den ekonomiska bättre val var att kombinera fjärrvärme med elpanna eller bergvärmepump.

The aim of this thesis is the analysis of the position of Italy from the socio-economic point of view in the EU in context of its most important aspect -- differentiation of the regions of North-Centre and South. The thesis is divided into three chapters. The first chapter deals with the comparative profile of Italy in EU including the causes and the development of the Italian social and economic specifics -- the high public debt, the slow economic growth rate and labour market problems. The basic macroeconomic and labour market indicators are used to determine the position of Italy in EU. The second chapter is aimed at the analysis of the primary causes, development and the current state of the Italian dualism on a theoretical level. The third chapter is dedicated to the description of Italian dualism by means of the concrete socio-economic indicators and deals with the comparison on the regional level. The part of this chapter deals with the efectiveness of application of EU regional policy in Italy.

In the last decade Process Synthesis has been an emerging active area of research. Since 1999 at COMPS, we have continuously applied this technique to many studies and recently have carefully started to consider the integration of this technique with others to simplify multilevel process design. In this regard the need for new tools that do not require very accurate data or experimental technique has become an imperative for the initial analysis of systems. This thesis presents some of these results.Process synthesis requires new rapid tools for the assessment and comparison of new technologies (possibilities) in the process development stage.This thesis examines and formulates process synthesis problems in the case of separation processes (separation with mixing , separation with reaction).Using simple generic vectorial tools, the thesis addresses the folowing issue: How the topology and mapping of the process vector field defines patterns that may be used for alternative process synthesis solution and design (structure selection ,stability analysis or controllability etc...) . The tools presented are intended for preliminary process design and feasibility studies and will allow for simple comparisons of various options.The key principle used in the study is the exploitation of the generic vectorial representation of fundamental physical phenomena (separation, mixing , reaction) in the process models as used for process synthesis and analysis.The demonstrated power of this approach is that it allows one to exploit the formal mathematical similarities between the different processing modes. Extensive topological Reactive Column Profile has been generated and analysed, offering new insights for manipulation of process behaviour in process synthesis and design. The significance of the contribution of this research is in offering extended fundamental insigths in creating process synthesis options for reactive-separations systems, creating the essential structural basis for subsequent mathematical optimisation of the performanceof process designs.

Student Number : 9903549T - MSc dissertation - School of Process and Materials Engineering - Faculty of Engineering and the Built Environment / Preliminary evaluations during flowsheet synthesis require simple effective tools for comparison and elimination of process alternatives. This work investigates three areas of interest in distillation. Column profile map theory has simplified complex column investigations. The predictions of the difference point equation at finite reflux were experimentally verified for the acetone, methanol and ethanol system in a continuous column apparatus. Residue curve analysis is usually limited to systems with four components for distillation system analysis. An alternative representation, based on combinatorial topology and temperature sequencing, is introduced for use in high level synthesis decisions for higher component order systems. Attainable region (AR) theory is applied to an ideal binary distillation system for a geometrically based method of cost analysis. A constrained attainable region is constructed from a series of equilibrium step compositions with varying reflux and corresponding cost associations. The AR is shown to be useful for costing and optimization.

Faculty of Engineering and the Built Environment; Master of Science in Engineering; Research Report / The primary objective of this study was to develop a methodology for evaluating how the reliability profile of the typical South African Platinum concentrator plant is affected by firstly the size of the primary milling units incorporated in the circuit and secondly by the way that the primary milling units are configured. A methodology, together with a set of general expressions is presented which considers the Platinum concentrator as a stochastic process where the behaviour of the primary mill is a direct measure of the failure pattern of the overall concentrator. The reliability, availability and maintainability (RAM) of the primary mill, and hence the overall concentrator, is then determined by a combination of three different Markov models where each Markov model is used to evaluate and measure a separate set of reliability parameters. This approach effectively overcomes the computational complexity associated with large Markov models. The results of two case studies used to validate the methodology do indicate that the reliability, availability and maintainability profiles of large single stream Platinum concentrators could be fundamentally different from the conventional multiple stream primary mill configurations.

Self-directed work groups are a growing phenomenon in the field of organisational psychology (Kauffeld, 2006; Neck & Manz, 1994). While much is known about what factors affect information sharing in these kinds of groups, little is known about why these factors have an impact and how they relate to each other. Through the concept of hidden profiles (tasks that by nature have shared and unshared information), this study explored the information sharing and group decision making processes and aimed to illuminate the group processes involved. The study employed a qualitative, ideographic approach where case studies were used. The sample consisted of twenty four undergraduate and postgraduate students studying at the University of the Witwatersrand divided into groups of four members each. A group task to rank the best candidate for a job was self-designed based on the theory and design utilized by Stasser and Titus (1985; 1987). This was first completed individually and then as a group – the group discussion was filmed and coded using a self-developed observation rubric. Participants also completed a self-developed post-task questionnaire regarding their perspectives of various aspects of the decision making process. The analysis was carried out using frequency counts and thematic content analysis. It was found that all the groups discussed more shared information and more unshared negative information was discussed than unshared positive information. Information sharing increased when there was debate about which pieces of information were relevant. In most cases, group members were motivated to share information because they wanted to have their opinion heard. Although the majority of the sample stated that they did not withhold any information, there was evidence of strategic information sharing. Group 5 made a decision that was closest to the ideal decision. Characteristics of this group that could have contributed to this included: long duration of discussion; high number of talking turns; respecting each other’s talking turns; moderate levels of disagreement; no obvious role of leader; moderately high levels of group familiarity; diversity in race not gender; similar educational backgrounds and a norm of critical evaluation. The study found that the interactions between factors that were perceived to affect the information sharing and decision-making (such as duration of discussion, number of talking turns, group familiarity, competitive aspects, group composition and group roles) were more interwoven than previously thought.

Student Number : 9510423G PhD Thesis School of Chemical and Metallurgical Engineering Faculty of Engineering and the Built Environment / Techniques for the design and analysis of simple column separations are well established. Shortcut design techniques have been employed in the initial design of these “traditional” distillation systems for a number of years and these columns are well understood. However, few currently available techniques are useful in the design of novel or complex configurations. The techniques that are available tend to be configuration specific. An all inclusive or universal, design and analysis tool, that can be applied to any and all configurations, is required. Tapp et al (2004) introduced Column Profile Maps (CPMS) as a means of addressing this issue. These are maps of composition profiles for column sections with defined net-molar-flow and reflux ratio. It is suggested that by producing CPMs for a configuration a designer can essentially superimpose these, determine feasible operating profiles and hence column operating parameters. In this thesis we show that this technique can be used to, not only produce quick and easy complex column designs but gain a comprehensive understanding of the steady-state operation of these arrangements. We demonstrate this analytical potential first by application of the CPM technique to the two-product feed distribution problem. It is shown that feed distribution can lower the minimum required reflux ratio for non-sharp separations and in some cases produce feasible separations from previously infeasible product specifications. A composition region of operation for all distributed feed policies is also found. The potential for detailed analysis, design and optimisation of complex configurations is demonstrated via application of the CPM procedure to the fully thermally coupled (Petlyuk) distillation column at both sharp and non-sharp split conditions. A detailed design methodology for any configuration results from this. It is found that the Petlyuk column can operate under five possible bulk/net flow conditions and that very interesting and counter-intuitive net-molar-flows are possible. A feasible column parameter region equivalent to the optimality region (Halvorsen and Skogestad, 2001) is found for zeotropic systems. Importantly a minimum reflux condition for the Petlyuk column is found. This condition can be applied to all zeotropic systems for all product specifications. It is also demonstrated that the CPM technique can be used for design optimisation of separation systems.